Supplemental device for attachment to a pen injector and determination of a set dose amount using optical incremental encoder

ABSTRACT

A data collection device comprises at least two optical sensors configured to detect tick marks of a medicament dose indicator of the medicament delivery device in their respective detection areas, and a processing arrangement configured to determine a current medicament dosage programmed into said medicament delivery device based on a count of the tick marks that pass through the detection areas of the optical sensors during programming of said medicament dosage into said medicament delivery device. A direction of travel of the tick marks may be identified, to determine whether the programmed dosage is increasing or decreasing. The apparatus may be arranged to identify a baseline dosage amount using a camera image of the medicament dosage indicator, so that a starting point for the count of tick marks can be determined. The medicament delivery device may be an injector pen.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/545,043, filed on Jul. 20, 2017, which is a U.S. national stageapplication under 35 USC § 371 of International Application No.PCT/EP2016/051245, filed on Jan. 21, 2016, which claims priority toEuropean Patent Application No. 15151912.1, filed on Jan. 21, 2015, theentire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an data and method for collectingmedicament dosage information from a medicament delivery device.

BACKGROUND

A variety of diseases exists that require regular treatment by injectionof a medicament. Such injection can be performed by using injectiondevices, which are applied either by medical personnel or by patientsthemselves. As an example, type-1 and type-2 diabetes can be treated bypatients themselves by injection of insulin doses, for example once orseveral times per day. For instance, a pre-filled disposable insulin pencan be used as an injection device. Alternatively, a re-usable pen maybe used. A re-usable pen allows replacement of an empty medicamentcartridge by a new one. Either pen may come with a set of one-wayneedles that are replaced before each use. The insulin dose to beinjected can then for instance be manually selected at the insulin penby turning a dosage knob and observing the actual dose from a dosagewindow or display of the insulin pen. The dose is then injected byinserting the needle into a suited skin portion and pressing aninjection button of the insulin pen.

To be able to monitor insulin injection, for instance to prevent falsehandling of the insulin pen or to keep track of the doses alreadyapplied, it is desirable to measure information related to a conditionand/or use of the injection device, for example, one or more of theinjected insulin type, dose and timing of the injection, in a mannerthat is reliable and accurate.

WO2011/117212 A1 discloses an apparatus configured for releasableattachment to a medical device or for releasably receiving at least apart of the medical device, such as an injection pen. The apparatuscomprises one or more optical sensors for determining informationrelating to a condition or use of the medical device, such as a dosageto be dispensed by the device, programmed into the device by a userusing optical character recognition.

SUMMARY

According to one aspect, there is provided a data collection deviceconfigured to be attached to, or releasably receive at least part of, amedicament delivery device, the data collection device, said datacollection device including at least two optical sensors, each arrangedto detect light from a respective detection area, and a processingarrangement, wherein the optical sensors are configured to detect tickmarks of a medicament dose indicator of the medicament delivery devicein their respective detection areas, and the processing arrangement isconfigured to determine a current medicament dosage programmed into saidmedicament delivery device based on a count of the tick marks that passthrough the detection areas of the optical sensors during programming ofsaid medicament dosage into said medicament delivery device.

Since the dosage is determined automatically during its programming, auser of the medicament delivery device is not required to perform anadditional action to cause recordal of the dosage. For instance, theuser is not required to take an image of the medicament dose indicatorspecifically for recording the medicament dosage.

In addition, the processing required for determining the dosage using a“light barrier” type technique may be less complex when compared withdevices that utilize a full optical character recognition algorithm,particularly as pre-processing to correct exposure levels and otherparameters may not be needed.

Also, where a camera is provided in the data collection device, thetechnical requirements for that camera in terms of resolution anddynamic range may be less onerous compared to cameras in devices thatrely fully on optical character recognition to determine a programmeddose. For example, a camera may be provided to capture an image of atleast a part of the medicament dosage indicator to determine an initialmedicament dosage displayed in the window corresponds to an expectedbaseline amount, such as zero units, so that the absolute value of thecount is known with certainty. Such a determination may be based onidentification of at least one character or marking shown in the image.Since there is an expected baseline amount, the processing arrangementmay be configured to compare the captured image with a templatecorresponding to a predicted image of the dosage window when theexpected baseline amount is displayed, to calibrate the count and/orconfirm that the count of tick marks will begin with an appropriateinitial value. If the captured image is not consistent with thetemplate, an audible and/or visual alert may be generated.

Where a camera is provided, the data collection device may include adisplay for showing the dosage displayed by the medicament dosageindicator, since the data collection device, when attached to themedicament delivery device, may obscure the user's view of themedicament dosage window. In such an embodiment, the displayed dosagesmay be calculated based on the expected baseline amount plus a currentcount of tick marks detected. Determining the dosages to be displayed tothe user in this manner can avoid the need for carry out a full opticalcharacter recognition process.

An order in which the sensors detect a tick mark passing through theirrespective detection areas may be used to determine a direction in whichthe tick mark is travelling. The direction of travel can then be used todetermine whether the programmed dosage is being increased or decreased.

The data collection device may be configured to determine that theprogrammed dosage is not being changed if the outputs of the opticalsensors are unchanged for a predetermined period of time.

The data collection device may be configured to be releasably attachedto the medicament delivery device, to allow it to be reused with othermedicament delivery devices. In a particular example, the medicamentdelivery device is a disposable injector pen, and the data collectiondevice can be reused with a second injector pen, or switched betweeninjector pens as needed.

This aspect also provides a medicament delivery system including any ofthe data collection devices discussed above, together with themedicament delivery device.

The medicament delivery device may be an injector pen. In particular,the medicament delivery device may be a disposable injector pen.However, in other embodiments, the data collection device may beconfigured for use with other medicament delivery devices.

According to another aspect, a method of collection dosage informationfrom a medicament delivery device includes, using two optical sensors,detecting tick marks of a medicament dosage indicator of the medicamentdelivery device, where said tick marks are present in a respectivedetection area of the two optical sensors, counting the tick marks thatpass through the detection area during programming of a medicamentdosage into the medicament delivery device, and, using a processingarrangement, determining a current medicament dosage programmed intosaid medicament delivery device based on a result of said count.

The method may also include, using a processing arrangement, determiningwhether the current medicament dosage is increasing or decreasing, basedon an order in which the optical sensors detect tick marks in saidrespective detection areas.

Alternatively, or additionally, the method may include determining aninitial medicament dosage displayed by the medicament dosage indicator,wherein the processing arrangement is configured to calculate thecurrent medicament dosage based on said initial medicament dosage andsaid count. In one example, determining an initial medicament dosagecomprises capturing an image of at least a part of the medicament dosageindicator using a camera and identifying at least one character or markin said image.

The method may include determining whether the count has changed withina predetermined time period and, if it is determined that the count hasnot changed during said predetermined time period, outputting anindication of a finalized medicament dosage programmed into themedicament delivery device, wherein said finalized medicament dosagecorresponds to the current medicament dosage.

In some embodiments, the medicament delivery device is an injector pen.For example, the medicament delivery device may be a disposable injectorpen for the delivery of insulin. However, the method may be used tocollect dosage information from injector pens for delivering othermedications or from other types of medicament delivery devices.

BRIEF DESCRIPTION OF THE FIGURES

Example embodiments of the present disclosure will now be described withreference to the accompanying figures, of which:

FIG. 1 is a perspective view of an example medicament delivery devicefrom which dosage information may be collected;

FIG. 2 is a detailed view of a portion of the medicament delivery deviceincluding a dosage window;

FIG. 3 is a perspective view of a data collection device according to anembodiment of the disclosure, attached to the medicament delivery deviceshown in FIG. 1;

FIG. 4 is a block diagram showing components of the data collectiondevice of FIG. 3;

FIG. 5 depicts an example of an optical sensor that can be used in thedata collection device of FIG. 3;

FIG. 6 shows an arrangement of two optical sensors in the datacollection device of FIG. 3;

FIGS. 7 and 8 depict intensities of light received by the opticalsensors and output signals from the optical sensors in the device ofFIG. 1 as a dosage is programmed into the medicament delivery device;

FIG. 9 is a flowchart of a method according to an embodiment of thedisclosure.

DETAILED DESCRIPTION

In the following, embodiments of the present disclosure will bedescribed with reference to collecting data from an insulin injectiondevice, such as Sanofi's SoloSTAR® pen. The present disclosure ishowever not limited to such application and may equally well be deployedwith injection devices that eject other medicaments, or other types ofmedicament delivery devices, or in applications other than thecollection of data from medicament delivery devices, as notedhereinabove.

FIG. 1 is an exploded view of a medicament delivery device. In thisexample, the medicament delivery device is an injection device 1, suchas Sanofi's SoloSTAR® insulin injection pen.

The injection device 1 of FIG. 1 is a pre-filled, disposable injectionpen that comprises a housing 10 and contains an insulin container 14, towhich a needle 15 can be affixed. The needle is protected by an innerneedle cap 16 and an outer needle cap 17, which in turn can be coveredby a cap 18. An insulin dose to be ejected from injection device 1 canbe selected by turning the dosage knob 12, and the selected dose is thendisplayed via dosage window 13, for instance in multiples of so-calledInternational Units (IU), wherein one IU is the biological equivalent ofabout 45.5 micrograms of pure crystalline insulin ( 1/22 mg). An exampleof a selected dose displayed in dosage window 13 may for instance be 30IUs, as shown in FIG. 1. It should be noted that the selected dose mayequally well be displayed differently.

The dosage window 13 may be in the form of an aperture in the housing10, which permits a user to view a limited portion of a number sleeve 71that is configured to move when the dosage knob 12 is turned.

Turning the dosage knob 12 causes a mechanical click sound to provideacoustic feedback to a user. The number sleeve 71 mechanically interactswith a piston in insulin container 14. When needle 15 is stuck into askin portion of a patient, and then injection button 11 is pushed, theinsulin dose displayed in the dosage window 13 will be ejected frominjection device 1. When the needle 15 of injection device 1 remains fora certain time in the skin portion after the injection button 11 ispushed, a high percentage of the dose is actually injected into thepatient's body. Ejection of the insulin dose also causes a mechanicalclick sound, which is however different from the sounds produced whenusing dosage knob 12.

Injection device 1 may be used for several injection processes untileither insulin container 14 is empty or the expiration date of injectiondevice 1 (e.g. 28 days after the first use) is reached.

Furthermore, before using injection device 1 for the first time, it maybe necessary to perform a so-called “prime shot” to remove air frominsulin container 14 and needle 15, for instance by selecting two unitsof insulin and pressing injection button 11 while holding injectiondevice 1 with the needle 15 upwards.

For simplicity of presentation, in the following, it will be exemplarilyassumed that the ejected doses substantially correspond to the injecteddoses, so that, for instance when making a proposal for a dose to beinjected next, this dose equals the dose that has to ejected by theinjection device. Nevertheless, differences (e.g. losses) between theejected doses and the injected doses may of course be taken intoaccount.

FIG. 2 is a close-up of the end of the injection device 1, showing alocating rib 70 that is located between the viewing window 13 and thedosage knob 12.

FIG. 3 shows a data collection device 2 according to an embodiment ofthe disclosure, that may be used to collect dosage information whenattached to the medicament delivery device 1.

In this particular embodiment, the data collection device 2 includes twohousing portions 2 a, 2 b connected by a hinge 2 c. The data collectiondevice 2 is releasably attached to the medicament device 1 by placing apart of the medicament delivery device 1 into a recess in one of thehousing portions 2 a, 2 b and closing the housing portions 2 a, 2 btogether around the housing 10 of the medicament delivery device 1. Thelocating rib 70 interacts with a co-operating formation 72 on the datacollection device so that the data collection device 2 is located at asuitable position on the medicament delivery device 1 to collect dosageinformation from the dosage window 13.

FIG. 4 is a block diagram of the data collection device 2. In thisparticular example, the data collection device is equipped with two ormore optical sensors 25 with an associated D flip-flop 29, a camera 24and a controller 26. The controller 26 is a processing arrangementincluding one or more processors, such as a microprocessor, a DigitalSignal Processor (DSP), Application Specific Integrated Circuit (ASIC),Field Programmable Gate Array (FPGA) or the like. The data collectiondevice 20 also includes memory units 240, 241, including program memory240 and main memory 241, which can store software for execution by thecontroller 26. The data collection device 20 also includes a wirelessunit 28 to permit bi-directional communication over a network, such as apersonal area network or Bluetooth® network, or a local wireless accessnetwork (WLAN). A display 21 and, optionally, an acoustical signalgenerator 23 are provided to allow visual and, if required, audiooutput. The data collection device 20 is powered by a battery 27 and apower button 22 is arranged to switch the device on and off.

For simplicity, the components of the data collection device 20 areshown in one block in FIG. 4. In the embodiment shown in FIG. 3, thecomponents are divided between the housing portions 2 a, 2 b of the datacollection device 20. For example, the display 21, the acoustical signalgenerator 23, where provided, and battery 27 may be provided in one ofthe housing portions 2 a, while the controller 26, the optical sensors25, the D flip-flop 29, the camera 24, the power button 22 and thewireless unit 28 may be provided in the other housing portion 2 b.

However, the division of the components of the data collection device 20are not limited to that particular configuration. In other embodiments,the housing portions 2 a, 2 b may include a different combination of thecomponents than the combinations described herein.

FIG. 5 is a circuit diagram of one optical sensor 25 a in the datacollection device 20 as an example. The optical sensor 25 a includes alight source 30 a, such as a light emitting diode (LED), and aphotodetector 31 a. In this particular example, the light source 30 aemits infra-red (IR) radiation at a wavelength of 940 nm.

When the data collection device 20 is attached to the medicamentdelivery device 1, the optical sensor 25 a is positioned over the dosagewindow 13 so that light emitted from the light source 30 a is incidenton tick marks 50 on the number sleeve 71 within a detection area 32 a ofthe optical sensor 25 a. Preferably, the housing portions 2 a, 2 b areconfigured to shield the detection area 32 a from ambient light, tofacilitate detection of the tick marks by the optical sensor 25 a.

Light is reflected from the number sleeve 71 is received by thephotodetector 31 a. The intensity of the light received by thephotodetector 70 at a particular moment indicates whether or not a tickmark 50 is present in the detection area 32 a. In this particularexample, the detection area 32 a is configured with a narrow width andthat the intensity of the received light increases as a tick mark 50 ismoved through the detection area 32 a and then decreases as the tickmark 50 leaves the detection area 32 a, until the next tick mark entersthe detection area 32 a. In other embodiments, the intensity of lightreceived by a sensor 25 a may, instead, decrease as a tick mark 50enters a detection area 32 a, depending on the reflectivity of the tickmarks relative to the background on the number sleeve 71.

In this particular embodiment, two optical sensors 25 a, 25 b areprovided, as shown in FIG. 6, each including a light source 30 a, 30 band a photodetector 31 a, 31 b arranged to monitor a respectivedetection area 32 a, 32 b.

In FIG. 6, the detection areas 32 a, 32 b are shown as being separated,for clarity. However, in this particular embodiment, the detection areas32 a, 32 b are arranged so that a tick mark 50 that is moved through thedosage window in a first direction will be detected by a first one ofthe optical sensors 25 b as it moves into the detection area 32 b forthat sensor. As the dosage continues increasing, the tick mark 50 willmove into the detection area 32 a of the other optical sensor 25 a. Theexample shown in FIG. 6 also includes a baseline detection marking 51 onthe number sleeve 71, which can be used to determine whether a baselinedosage amount is shown in the dosage window 13.

FIG. 7, part (a) shows examples of the light intensities received by theoptical sensors 25 a, 25 b, in an arrangement where the detection areas32 a, 32 b are positioned closely as described above. As a user turnsthe knob 12 to increase the dosage, tick mark 50 enters the detectionarea 32 b, the output of optical sensor 25 b, shown as a solid line,increases and remains high until the tick mark 50 a moves out of thedetection area 32 b. The received light intensity remains low until asubsequent tick mark 50 b enters the detection area 32 b.

Before the tick mark 50 a leaves detection area 32 b, its leading edgemoves into detection area 32 a and the intensity of light received byoptical sensor 25 a, shown as a dashed line, also increases until thetick mark 50 a leaves the detection area 32 a.

FIG. 7, parts (b) and (c) show signals output by the optical sensors 25a, 25 b respectively. These signals have a high or low level dependingon whether the intensity of the light received by those sensors 25 a, 25b exceeds a predetermined threshold. The solid line depicts the outputfrom sensor 25 b, while the dashed line depicts the output from sensor25 a. In this particular embodiment, the count is increased when atrailing edge of each tick mark 50 a, 50 b leaves detection area 32 a.The timings at which the count is increased are indicated as t1 and t2.

FIG. 8 depicts the received light intensities and optical sensor outputsin an example where the user completes the programming of the dosage attime t3. In this particular example, a tick mark is present in detectionarea 32 b but has only just begun to enter detection area 32 a. Thecontroller 26 is configured to detect when a predetermined period oftime tx has elapsed without a change in the output signals or,alternatively, in the count itself. In this example, time tx is set to 8seconds.

At time t4, the time period tx has elapsed, and the controller 26determines that the finalized medicament dosage is the initial dosageadjusted by the result of the count.

In addition to being used by the controller 26 for the count itself, thesignals from the optical sensors 25 a, 25 b are provided as inputs tothe D flip-flop 29. The output from the D flip-flop 29, based on theorder in which rising edges of the signals from the optical sensors 25a, 25 b are detected, will be a high level or a low level and, thereforedepends on the direction in which the tick marks are moved. Hence, thecontroller 26 can determine the direction of travel and whether themedicament dosage is being increased or decreased, based on the outputsignal from the D flip-flop 29.

A method of collecting dosage information will now be described, withreference to FIG. 9.

Starting at 9.0, the camera 24 is used to capture an image of at leastpart of the dosage window 13 (step s9.1).

This image is then processed by the controller 26 to determine whetherthe dosage currently displayed in the dosage window is an expectedinitial value (step s9.2). For example, some injector pens automaticallyreduce the number 19 displayed in the dosage window 13 to zero when aninjection is administered, and so it would be expected that the initialvalue shown in the dosage window 13 before a user programs a dosage fora subsequent injection, should read zero or another expected baselinedosage amount, or display a character indicating the same. If this checkis not made, then the actual dosage programmed into the injection pen 1cannot be determined with certainty.

As noted above, in this particular example a baseline detection marking51 is included on the number sleeve 71. The baseline detection marking51 may be a pattern or other mark, such as a two-dimensional code thatcan be detected by the camera 24, where provided. The baseline detectionmarking 51 may be visible at optical wavelengths and/or visible at otherwavelengths. In this particular example, the baseline detection marking51 is printed onto the number sleeve 71 using ink that is visible atinfra-red (IR) wavelengths and the camera 24 is configured to besensitive to IR radiation reflected from the number sleeve 71 to detectthe baseline detection marking 51. Since the position of the camera 24relative to the dosage window 13 is fixed by the locating rib 70, thebaseline detection marking 51 would be expected to appear at aparticular position in an image captured by the camera 24 when thedisplayed dosage matches the expected baseline dosage amount. In theexample shown in FIG. 6, the expected baseline dosage amount is zero IU.

Alternatively, or additionally, the determination of whether themedicament dosage initially shown in the dosage window 13 corresponds tothe expected baseline dosage amount may use the numerical charactersprinted on the number sleeve 71. In one example, one or more of thevisible characters is selected, for example, the character or charactershaving the greatest height. Pattern matching is performed, based on atemplate stored in the one of the memories 240, 241 of the datacollection device 20 that corresponds to the expected baseline dosage.Since the position of the camera 24 relative to the dosage window 13 isfixed by the locating rib 70, the selected character should provide areasonable for the template if it corresponds to the expected baselinedosage. The comparison may be made on a pixel-by-pixel basis, or using afeature recognition process or a vector comparison process, for example.

In another embodiment, the selected character may be identified using amore elaborate optical character recognition process.

The confirmation of the medicament dosage amount initially displayed inthe dosage window 13 using a baseline detection marking 51 and/orrecognition of the numerical characters on the number sleeve 71 canallow an actual value of the programmed dosage to be determined withcertainty, without requiring the user to perform specific steps tocalibrate the measurement to be made.

If it found that the dosage displayed in the dosage window 13 is notconsistent with the expected baseline dosage (step s9.2), an alertmessage is generated and presented on the display 21 and/or as anaudible alarm using the acoustical signal generator 23 (step s9.3).

If the displayed dosage is consistent with the expected baseline dosage(step s9.2), then the data collection device 20 begins to monitor thedosage window 13 using the optical sensors 25 a, 25 b (step s9.4) todetect tick marks 50 being moved through the detection areas 32 a, 32 b.If changes to the output of the optical sensors 25 a, 25 b are detectedwithin the predetermined time period tx (step s9.5), then the outputfrom the D flip-flop 29 is used to determine whether the dosageprogrammed into the injection pen 1 is being increased or decreased(step s9.6), as discussed herein above.

The count is then adjusted (step s9.7) and the current dosage isdetermined (step s9.8). The output of the display 21 is updated to showthe newly determined current dosage (step s9.9).

Steps s9.4 to s9.9 are repeated, so that the count and the currentdosage presented on the display 21 continue to be updated based on thedetection of tick marks by the optical sensors 25 a, 25 b.

When the user has finished programming the dosage into the injection pen1, the optical sensors 25 a, 25 b will not detect further changes. Iftime period tx has elapsed since previous changes in the optical sensorsoutputs (step s9.5) or, in an alternative embodiment, if there have beenno changes to the count during the time period tx, then the currentdosage is taken to be the final medicament dosage (step s9.10), that is,the dosage that will be administered by the user. In some embodiments, amessage might be output using the display 21 and/or the acousticalsignal generator 23 to prompt the user to confirm the final medicamentdosage.

The final medicament dosage is then stored (step s9.11) in the programmemory 240 and, optionally, transmitted to another device (step s9.12),such as a computer, tablet device or smartphone, using the wireless unit28.

The data collection process then ends (step s9.13).

While the embodiments above have been described in disclosure relationto collecting data from an insulin injector pen, it is noted thatembodiments of the disclosure may be used for other purposes, such asmonitoring of injections of other medicaments or other medicalprocesses.

1. A data collection device configured to be attached to, or releasablyreceive at least part of, a medicament delivery device, the datacollection device comprising: at least two optical sensors, eacharranged to detect light from a respective detection area; and aprocessing arrangement; wherein: the optical sensors are configured todetect tick marks of a medicament dose indicator of the medicamentdelivery device in their respective detection areas; and the processingarrangement is configured to determine a current medicament dosageprogrammed into said medicament delivery device based on a count of thetick marks that pass through the detection areas of the optical sensorsduring programming of said medicament dosage into said medicamentdelivery device.
 2. A data collection device according to claim 1,wherein configured to determine whether the current medicament dosage isincreasing or decreasing, based on an order in which the optical sensorsdetect tick marks in said respective detection areas.
 3. A datacollection device according to claim 1 or 2, configured to determine aninitial medicament dosage displayed by the medicament dosage indicator,wherein the processing arrangement is configured to calculate thecurrent medicament dosage based on said initial medicament dosage andsaid count.
 4. A data collection device according to claim 3, comprisinga camera configured to capture an image of at least a part of themedicament dosage indicator, wherein the processing arrangement isconfigured to determine the initial medicament dosage by identifying atleast one character or mark shown in said image.
 5. A data collectiondevice according to claim 4, wherein said processing arrangement isconfigured to identify said at least one character based on a storedtemplate corresponding to an expected initial medicament dosage.
 6. Adata collection device according to any of the preceding claims,configured to output an indication of the current medicament dosage inresponse to a change in the count.
 7. A data collection device accordingto any of the preceding claims, wherein the processing arrangement isconfigured to determine whether the count has changed within apredetermined time period and, if it is determined that the count hasnot changed during said predetermined time period, output an indicationof a finalised medicament dosage programmed into the medicament deliverydevice, wherein said finalised medicament dosage corresponds to thecurrent medicament dosage.
 8. A medicament delivery system comprising: adata collection device according to any of the preceding claims; andsaid medicament delivery device.
 9. A medicament delivery systemaccording to claim 8, wherein said medicament delivery device is aninjector pen.
 10. A method of collection dosage information from amedical delivery device, comprising: using two optical sensors,detecting tick marks of a medicament dosage indicator of the medicamentdelivery device, where said tick marks are present in a respectivedetection area of the two optical sensors; counting the tick marks thatpass through the detection area during programming of a medicamentdosage into the medicament delivery device; and using a processingarrangement, determining a current medicament dosage programmed intosaid medicament delivery device based on a result of said count.
 11. Amethod according to claim 10, comprising, using a processingarrangement, determining whether the current medicament dosage isincreasing or decreasing, based on an order in which the optical sensorsdetect tick marks in said respective detection areas.
 12. A methodaccording to claim 10 or 11, comprising determining an initialmedicament dosage displayed by the medicament dosage indicator, whereinthe processing arrangement is configured to calculate the currentmedicament dosage based on said initial medicament dosage and saidcount.
 13. A method according to claim 12, wherein said determining aninitial medicament dosage comprises capturing an image of at least apart of the medicament dosage indicator using a camera and identifyingat least one character or mark shown in said image.
 14. A methodaccording to any of claims 10 to 13, comprising determining whether thecount has changed within a predetermined time period and, if it isdetermined that the count has not changed during said predetermined timeperiod, outputting an indication of a finalised medicament dosageprogrammed into the medicament delivery device, wherein said finalisedmedicament dosage corresponds to the current medicament dosage.
 15. Amethod according to any of claims 10 to 14, wherein said medicamentdelivery device is an injector pen.